Deleting and updating db after changing model class? - c#

Hi I'm working with the mvc 5 framework in ASP.Net on a course I'm taking at my school, but I seem to have hit a wall.
I want to go back and add a field value to my main model (Student) class, but of course that means the structure of the database has to change (getting errors when I try to run it). I was told this should be doable with the command "enable-migrations -enableautomaticmigrations" typed into the Package Manager Console, but I seem to get an error message saying it's an unknown command when I type it. Or am I supposed to do something different than using these commands?
Here is the error I'm getting when I write the aforementioned command:
PM> enable-migrations
The term 'enable-migrations' is not recognized as the name of a
cmdlet, functio n, script file, or operable program. Check the
spelling of the name, or if a pa th was included, verify that the path
is correct and try again. At line:1 char:18
Any help is appreciated!

I wonder if you tried reinstalling Entity framework Install-Package EntityFramework -IncludePrerelease. Sometimes the Prerelease version is not included. Try that. If not try Update-Database -Force if you already have a database. One last way is to reopening the project after closing everything in VS.

The problem was that my project was located in my dropbox. For some reason my visual studio doesn't like that, moved it locally and everything worked.

Related

Mapster.Tool Code Generation for Specific Project

I have a Visual Studio solution containing various sample console app projects. One of which is MapsterSample where I am trying out Mapster and following the steps described on GitHub https://github.com/MapsterMapper/Mapster/wiki/Mapster.Tool to generate mapping code.
Everything seems fine except for the part where I issue the command:
dotnet msbuild -t:Mapster
This results in the command executing for every project in the solution even if MapsterSample is selected as Default project in Package Manager Console:
SampleSolution\FirstSample\FirstSample.csproj : error MSB4057: The target "Mapster" does not exist in the project.
SampleSolution\SecondSample\SecondSample.csproj : error MSB4057: The target "Mapster" does not exist in the project.
... and so on
Is there a way to just execute the command for the MapsterSample project?
Make sure the project exists within your solution.
Make sure that the name Mapster is spelled correctly.
Make sure your terminal is in the correct directory. (ideally you should be in the directory ABOVE the directory the .csproj for Mapster is in.

EF Core set environment not working predictably

When I go to update my database I run $env:ASPNETCORE_ENVIRONMENT="Development" first before executing the Update-Database command to set the correct environment. If I had previously deployed changes to Test for example, running this command should point me back to my Development environment and no longer be pointing at Test.
Unfortunately this only works maybe 33% of the time. Every time I run this I also run $env:ASPNETCORE_ENVIRONMENT and check that it returns back the correct environment and it does. Then I run the Update-Database command that I need and it somehow changes back to the previous environment.
Anyone have any idea on either what I am doing wrong or a way to know that I will be connected to the correct DB? This could be very bad if the wrong database is hit and data happens to get deleted or a system goes down.
The way that I have worked around this for the past couple of years is to have a second terminal window (I use cmder so I can use a linux based command line environment) and use dotnet commands from there. So far I haven't had any issue doing this and don't have any faith in the package manager console.
Commands take the form of the following:
Set current environment set ASPNETCORE_ENVIRONMENT=development
Add new Migration:
dotnet ef migrations add MyNewMigration
Revert Migration: dotnet ef migrations remove
Rather than exporting the variable at command line, you should set/export the variables within the database update script. So if you are running a shell script, you can export via standard export commands. If you are running perl/python, you should update the environment variables within the script. That way, you will have consistent behavior.

Can't reverse engineer SQL Server database table

I'm trying to create a Web API. I'm following some examples but I can't get anything to work.
The examples say to use this
Scaffold-DbContext connection_string Microsoft.EntityFrameworksCore -OutputDir Models
I don't want to do all the tables so I looks at the "Package Manager Console" help for the command and am told this
-Tables <String[]>
The tables to generate entity types for.
Required? false
Position? named
Default value #()
Accept pipeline input? false
Accept wildcard characters? false
So I've tried this
Scaffold-DbContext connection_string Microsoft.EntityFrameworksCore -OutputDir Models -Tables dbo.table
I'm changing the names of the connection string and tables. I don't want to do all the tables because there are 70+ tables in this db.
When I try that all I get back is.
"Build Failed"
That's pretty terse so when I stick on -Verbose all I get is
Using project 'ArgusApi'.
Using startup project 'ArgusApi'.
Build started...
Build failed.
A little more verbose, but not much. I was getting more error messages but I cleaned those up to just this.
Any help is much appreciated.
The "Build Failed" message simply means that your project doesnt build. (In Visual Studio) Press F5 and try to build your project. If it cant be built cleanly, then when you run "Scaffold-DbContext" you will get this message.
Usually this happens because your entities/pocos are in some sort of broken state. Delete all your models so they dont break the build and try again.

SqlException: Invalid object name 'Movie'

I am trying to follow the tutorial from the link below to create an app that shows a list of movies from a database with crud functionality, but I am trying to add a user login.
https://learn.microsoft.com/en-us/aspnet/core/tutorials/first-mvc-app/
I have been trying to figure out how to add and update the migrations for the Movie database. I am able to do it when I follow the tutorial without the user login, but once I add the user login, there seems to be an issue that I am not catching.
After I create the model class, I am trying to apply the following steps for the migration
Goto the command line and access the folder with the project in
it
apply the following commands
dotnet restore
dotnet ef migrations add --context MvcMovie2Context (When I run this command, I get (Missing required argument ''.) error)
dotnet ef database update --context MvcMovie2Context
(This command seems to be working for some reason)
When I run the app and click on the movie link, I get the following error
SqlException: Invalid object name 'Movie'.
System.Data.SqlClient.SqlCommand+<>c.<ExecuteDbDataReaderAsync>b__107_0(Task<SqlDataReader> result)
I have looked through my Model, View and Controller classes to check if I made a typo or a syntax error that would cause the object name ‘Movie’ to be invalid, so I think it means that my Movie database was not created.
I have restarted the project multiple times following the tutorial
I have attached screenshots of the command line errors and browser error. I would greatly appreciate if anyone has any hints or suggestions that they could provide me. Thanks!
I had a similar error even though all the tables were properly created. It turned out that my connection string was wrong.
Since the error is SqlException: Invalid object name 'Movie', that means the table named 'Movie' has not created or the Database you are referring has not created.
To see if the Database or table 'Movie' has created, open SQL Server Object Explorer and check the Database name is the same as in appsettings.json. If the Database or table has not created, you may need a migration.
To migrate, open Tools-> NuGet Package Manager-> Package Manager Console and hit the following commands:
Add-Migration MigrationName
Update-Database
Then check SQL Server Object Explorer again or build and run your project.
Do you have a Movies or Movie table in your database?
Since you say that dotnet ef migrations add --context MvcMovie2Context fails, leads me to believe that your model has not been reflected in the database schema. Also, as far as I know, you need to provide a migration name, which is probably why you are receiving the error.
Please try running the following commands.
1.dotnet ef migrations add "AddedMovieEntity" --context MvcMovie2Context
2.dotnet ef database update --context MvcMovie2Context
Hopefully this time step 1 will run successfully, from there you should see a migration file that includes the schema for the Movie entities. After step 2, you should see the respective table in your database.

Visual studio - getting error "Metadata file 'XYZ' could not be found" after edit continue

I have stumbled into an issue that is really annoying.
When I debug my software, everything runs OK, but if I hit a breakpoint and edit the code, when I try to continue running I get an error:
Metadata file 'XYZ' could not be found
After looking around for a while, I found some a similar issues, but they were all regarding a build failure, which is not my case (this happens only after edit-continue).
What I have tried so far:
My code is compiling and running.
I cleaned the solution and restarted VS.
I made sure that the missing file's project is being build for the configuration I am running (in configuration manager).
I manually built the missing file's project.
Some extra info:
It does not matter what I change, still get the same error (the change is not related to the missing file).
This happens also when I pause and continue (not only breakpoints)
I am running the project using a custom configuration (configuration manager...). When I run it using the default Debug configuration the error does not occur.
Any ideas?
Eventually what solved the issue was:
Clean every project individually (Right click> Clean).
Rebuild every project individually (Right click> Rebuild).
Rebuild the startup project.
I guess for some reason, just cleaning the solution had a different effect than specifically cleaning every project individually.
Edit:
As per #maplemale comment, It seems that sometimes removing and re-adding each reference is also required.
Update 2019:
This question got a lot of traffic in the past, but it seems that since VS 2017 was released, it got much less attention.
So another suggestion would be - Update to a newer version of VS (>= 2017) and among other new features this issue will also be solved
As far as I can tell, this happens when the project dependencies gets messed up for whatever reason (whilst all the inter-project references are still intact). For many cases, it is NOT a code issue. And for those who have more than a few projects, going through them one at a time is NOT acceptable.
It's easy to reset project dependencies -
Select all projects and right click unload
Select all projects and right click reload
Rebuild solution
For those who have an issue in their code or some other issue that's causing this problem you'll obviously have to solve that issue first.
One possible reason could be you have upgraded the some of your projects (in the solution) to higher version e.g. from .NET 4.0 to 4.5 This happened in my case when I opened the solution in VS 2013 (originally created using VS 2010 and .NET 4.0). When I opened in VS 2013 my C++ project got updated to .NET 4.5 and I started to see the problem.
Generally this kind of error comes with human mistakes like if we change the namespace in some improper way, or changing folder names from explorer for current project etc, where compiler is unable to detect sometimes.
I came across the same error, to resolve which I tried few steps. Please follow all the steps :
Clean whole Solution
Right Click on every Project in your solution , Go to Properties and make your Default namespace as well as Default assembly name same as in your code (i.e namespace before class name)
Check Folder names for each project by going through the explorer(Where your project solution is). If not matching with your project names, make it similar (Like step 2) to them.
Remove all your references from each project relevant to another of same solution, and add it again.
In Your Project Solution folder, you will find Visual c# Project file. Right click and open with Notepad. In your initial lines you would find for lines for every project like below:
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "**Client**", "**Client** \ **Client**.csproj", "{4503E259-0E3B-414A-9074-F251684322A5}"
EndProject
Check again Foldernames (I have highlighted in BOLD) and make it similar to what you did in step 2.
Clean the whole solution again
Build The Solution (If doesn't work try building individual after cleaning again)
Make sure all your dependent projects are using the same .Net Framework version. I had the same issue caused by a dependent project using 4.5.1, while all others were using 4.5. Changing the project from 4.5.1 to 4.5 and rebuilding my solution fixed this issue for me.
XYZ couldn't be found because is not built yet....
Right click on the solution and check Project Dependencies, the Project Build Order should also change according to the dependencies that have been set.
The only thing that worked for me was to delete the Solution User Options (.suo) file. Note that, this is a hidden file.
To locate this file, close your Virsual studio and search for .suo from the file explorer within your project.
PS: a new .suo file will be created again when you rebuild your project and hopefully this newly created one wont give you issues.
I hope that helps someone get rid of this anoying error :).
I had this problem for days! I tried all the stuff above, but the problem kept coming back. When this message is shown it can have the meaning of "one or more projects in your solution did not compile cleanly" thus the metadata for the file was never written. But in my case, I didn't see any of the other compiler errors!!! I kept working at trying to compile each solution manually, and only after getting VS2012 to actually reveal some compiler errors I hadn't seen previously, this problem vanished.
I fooled around with build orders, no build orders, referencing debug dlls (which were manually compiled)... NOTHING seemed to work, until I found these errors which did not show up when compiling the entire solution!!!!
Sometimes, it seems, when compiling, that the compiler will exit on some errors... I've seen this in the past where after fixing issues, subsequent compiles show NEW errors. I don't know why it happens and it's somewhat rare for me to have these issues. However, when you do have them like this, it's a real pain in trying to find out what's going on. Good Luck!
Well, my answer is not just the summary of all the solutions, but it offers more than that.
Section (1):
In general solutions:
I had 4 errors of this kind (‘metadata file could not be found’) along with 1 error saying 'Source File Could Not Be Opened (‘Unspecified error ‘)'.
I tried to get rid of ‘metadata file could not be found’ error. For that, I read many posts, blogs etc and found these solutions may be effective (summarizing them over here):
Restart VS and try building again.
Go to 'Solution Explorer'. Right click on Solution. Go to Properties. Go to 'Configuration Manager'. Check if the checkboxes under 'Build' are checked or not. If any or all of them are unchecked, then check them and try building again.
If the above solution(s) do not work, then follow sequence mentioned in step 2 above, and even if all the checkboxes are checked, uncheck them, check again and try to build again.
Build Order and Project Dependencies:
Go to 'Solution Explorer'. Right click on Solution. Go to 'Project Dependencies...'. You will see 2 tabs: 'Dependencies' and 'Build Order'. This build order is the one in which solution builds. Check the project dependencies and the build order to verify if some project (say 'project1') which is dependent on other (say 'project2') is trying to build before that one (project2). This might be the cause for the error.
Check the path of the missing .dll:
Check the path of the missing .dll. If the path contains space or any other invalid path character, remove it and try building again.
If this is the cause, then adjust the build order.
Are you using a database code generation tool like SQLMETAL in your project?
If so, you may be facing a pluralized to unpluralized transition issue.
In my case, I have noted that some old pluralized (*) table names (upon which SQLMETAL adds, by default, an "s" letter at the end) table references to classes generated by SQLMETAL.
Since, I have recently disabled Pluralization of names, after regerating some database related classes, some of them lost their "s" prefix. Therefore, all references to affected table classes became invalid. For this reason, I have several compilation errors like the following:
'xxxx' does not contain a definition for 'TableNames' and no extension method 'TableNames' accepting a first argument of type 'yyyy' could be found (are you missing a using directive or an assembly reference?)
As you know, I takes only on error to prevent an assembly from compiling. And that is the missing assemply is linkable to dependent assemblies, causing the original "Metadata file 'XYZ' could not be found"
After fixing affected class tables references manually to their current names (unpluralized), I was finnaly able to get my project back to life!
(*) If option Visual Studio > Tools menu > Options > Database Tools > O/R Designer > Pluralization of names is enabled, some SQLMETALl code generator will add an "s" letter at the end of some generated table classes, although table has no "s" suffix on target database. For further information, please refer to http://msdn.microsoft.com/en-us/library/bb386987(v=vs.110).aspx
Hope it helps!
I had this error come up. I followed all of the solutions here but nothing worked. I was using Visual Studio 2013 Professional. I couldn't get the individual project rebuilds to work and I finally figured out there was a circular dependency in my references. Visual Studio does a pretty good job normally of warning you if you are adding a reference to something that references back, but for some reason it didn't in this instance. I added a reference to a project that referenced the project I was working on - and it accepted it. VS bug perhaps?
My 5 cents.
This problem started after a solution wide clean.
I managed to get the problem to go away by setting the Active Solution configuration in: Build -> Configuration manager to release. Then build and set it back to debug again. The build succeeded after that.
Close VS, locate and remove the 'packages' folder from outside of visual studio. Restart VS and build -> all dependencies are reinstalled
Visual Studio 2019 Community 16.3.10
I had similar issue with Release build. Debug build was compiling without any issues.
Turns out that the problem was caused by OneDrive. Most likely one could experience similar issues with any backed-up drive or cloud service.
I cleaned everything as per Avi Turner's great answer.
In addition, I manually deleted the \obj\Release -folder from my OneDrive folder and also logged to OneDrive with a browser and deleted the folder there also to prevent OneDrive from loading the cloud version back when compiling.
After that rebuilt and everything worked as should.
this happens because of the difference of names in the folder name and namespace name. If u create a namespace in a certain name , and later you rename it the namespace will have the old name itself. And the compilation will take the old path to find the .dll and .exe file . To avoid this open the .csproj file of each namespace with a text file , and find the old path in the file.
remove this, clean and rebuild the solution. This worked for me. I spent an entire day working on this problem.
I had this and managed to fix it using this SO answer:
Metadata file '.dll' could not be found
I had to uncheck all of the boxes, click Apply, reenable all of the checkboxes and then click apply again, but it fixed the problem.
I just ran into this issue and after an hour of screwing around realized I had added an aspx file to my product that had the same name as one of my Linq-To-Sql classes.
Class and Page where "Queue".
Changed the page to QueueMgr.aspx and everything built just fine.
For a new build, it could be that some dependencies aren't installed. For me it was Crystal Reports.
It happens when one project dll is failing and that is referenced by number of projects. So first fix it and then Build individuals.
I ve had this problem and it has started after importing our solution to TFS as a new project.I came across this topic and found a quick solution with some inspiration from your answers.
All i needed to do is to rebuild the project thats supposedly lost its metadata file and voila , problem solved.
There's also one another silly reason which you should check with patience... as it occurred to me after wasting 4hours searching for answers:
The story to me was that I accidentally changed a small line of code among thousands of c# class files and then trying to rebuild the solution. As you could imagine, I ended up with 40+ meta data file missing errors and with 1 compilation error among them -- which I didn't check carefully, purely thinking all errors were the same!
after 4 hours searching and then accidentally double checking my error list, I found that silly code error, fixed it, compiled, and then error disappeared.
Not a good answer to your problem, but do hope my case wasn't same to yours.
I had the same problem. In my case I had by mistake I had set all the projects apart from the project with the main method as console application.
To resolve I went to every project other than the one with main function and right click> properites > output type > class library
it was happened to me because I've a strange clash in the namespaces:
I had
AssemblyA
with namespace
AssemblyA.ParentNamespace
witch defines ClassA
and in the same assembly another namespace with name
AssemblyA.ParentNamespace.ChildNamespace
witch defines a different ClassA (but with the same name)
I had then in AssemblyA.ParentNamespace IInterfaceB witch had a method that in the beginning returns IEnumerable and a ClassB witch implements IInterfaceB
I had later modified the method in ClassB to return IEnumerable but I've forgot to update the IInterfaceB definition, so the method there was still returning IEnumerable
the fun fact was that the solution still complile if I did a rebuild all, but the tests witch refers AssemblyA didsn't work and returns the "Metadata file could not be found"error.
updating InterfaceB to correctly return IEnumerable as its implementor ClassB did solved the problem, unfortunately the error message was vague and also the fact that the compilation worked makes me suppose that maybe there is something to fix in the compiler
A coworker was running into this problem and the cause was eluding us. Eventually we realized that the project directory (and therefore the path to the NuGet packages) contained %20 (thanks, some Git gui tool which shall not be named) and the error messages showed that the compiler was looking for an very similar-looking path but one which had to %20, rather a space. Apparently something in the build system somewhere performs HTML-decoding on local filesystem paths.
Renamed the working copy directory and everything started working.
I had this issue too.
It started after I did a little folder tidying in my project.
I then tried to compile and got many duplicate class errors. (despite them not being duplicated. I think the linking was just out of wack)
Upon checking these, the errors would all disappear leaving only the "Metadata file ...debug\application.exe could not be found" error.
I solved this by looking in the build output window to find which classes were duplicated.
I would then right click the class name and "go to definition".
there will be two definitions to select from, open them both, the second definition will seem to open the same file again, however the second one will identify as the error source(red underline).
Delete all the code out of the file and save(This will not effect your actual file).
This should now compile correctly.
Ensure that there are no spaces in the path to your project...
I am using Windows 10 with Visual Studio Community 2019 and I was cloning a multi project solution as it was from a GIT repo. I was having this error with all other dependencies in the solution along with a E_POINTER error. Its path, inherited from GIT, had spaces like C:/repos/MY PROJECT NAME/ ...
I deleted it, cloned it again and make sure that its path contained no spaces like C:/repos/MY_PROJECT_NAME/ ...
That fixed my problem.
I had same issue too.
In my case, I recently add an internal class to somewhere in project. One of the dependencies in solution has same class name and both of them are added correctly to references.
I changed my last activity and rebuild, it works.
Be sure that your compiler messages are valid. In my case I catch reference error from there, not listed as an error in Error List.

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